IAB Downlink Timing

ABSTRACT

There is disclosed a method of operating an Integrated Access and Backhaul (IAB) node (200, C, N3) in a radio access network, the IAB node (200, C, N3) being connected to a first parent IAB node (200, N1, P) via a first backhaul link having a first timing, and being connected to a second parent IAB node (200, N2, P) via a second backhaul link having a second timing, the IAB node (200, C, N3) providing a communication link for access or backhaul, the communication link having a communication timing based on the first timing and the second timing. The disclosure also pertains to related methods and devices.

TECHNICAL FIELD

This disclosure pertains to wireless communication technology, inparticular in the context radio access technologies.

BACKGROUND

For radio access networks, radio nodes are connected to a core network,to allow communication between terminals in different cells provided bydifferent radio nodes. The radio nodes are usually connected to the corenetwork by wire or cable, in particular via optical fibre. However, itis not always practical or feasible to arranged such a land-boundconnection. For such cases, there may be employed relay nodes or nodesfor integrated access and backhail (IAB). An IAB node may on the onehand provide radio access to terminals or user equipments (UEs), and onthe other hand may communicated to a parent (IAB) node via radiotechnology, to be relayed or routed to a core network, e.g. via a donornode. Due to sharing time/frequency resources with terminals and othernodes, the use of IAB nodes requires new approaches of managingresources and node behaviour.

SUMMARY

It is an object of the present disclosure to provide approachesfacilitating improved IAB handling.

The approaches are particularly advantageously implemented in a 5^(th)Generation (5G) telecommunication network or 5G radio access technologyor network (RAT/RAN), in particular according to 3GPP (3^(rd) GenerationPartnership Project, a standardisation organization). A suitable RAN mayin particular be a RAN according to NR, for example release 15 or later,or LTE Evolution.

There is disclose a method of operating an Integrated Access andBackhaul (IAB) node in a radio access network. The IAB node is connectedto a first parent IAB node via a first backhaul link having a firsttiming, and being connected to a second parent IAB node (200, N2, P) viaa second backhaul link having a second timing, the IAB node (200, C, N3)providing a communication link for access or backhaul, the communicationlink having a communication timing based on the first timing and thesecond timing.

There is also disclosed a network node for a radio access network, thenetwork node being an Integrated Access and Backhaul (IAB) node. The IABnode is adapted to be connected or connectable to a first parent IABnode via a first backhaul link having a first timing, and beingconnected or connectable to a second parent IAB node via a secondbackhaul link having a second timing. The IAB node is adapted forproviding a communication link for access or backhaul, the communicationlink having a communication timing based on the first timing and thesecond timing. The IAB node may comprise, and/or be adapted forutilising, processing circuitry and/or radio circuitry, in particular atransceiver and/or receiver and/or transmitter, for providing thecommunication link and/or for operating on the first backhaul linkand/or the second backhaul link.

The first and second backhaul links may be in a set of parent backhaullinks to a number of parent node larger than two. Any link-specificparameter mentioned may pertain to one of the link provides by a parentof the set. A backhaul link from a parent IAB node (also referred to asparent node) may be controlled regarding timing and/or synchronisationby the parent, e.g. via DCI signaling and/or SS/PBCH block signaling, inparticular with signaling indicating timing advance and/or timingadvance adjustment, and/or primary and/or secondary synchronisationsignaling. Alternatively, or additionally, the backhaul link may bepower-controlled by the parent node, e.g. via TPC commands in DCI. Ingeneral, the parent node may control physical layer aspect ofcommunication with a child node (the IAB node) with suitable controlsignaling, e.g. DCI signaling. A backhaul link may generally be awireless connection between network nodes (IAB nodes), over whichsignaling from a (wireless or radio) access link or another backhaullink may be carried or transported or routed, e.g. to another IAB node.In particular, signaling between a terminal not in direct radio accesswith a donor node may be carried over one or more backhaul links. Thebackhaul links may be in mm-wave ranges. It may be considered thatbackhaul link and access links are in different frequency ranges and/orcarriers. For example, access links may be lower in frequency, e.g.below 6 GHz. Backhaul links may share a frequency range and/or carrierand/or carrier aggregation.

Providing a communication link may comprise providing a cell and/oruplink and/or downlink communication for the link, e.g. for accessand/or backhaul. The IAB node may provide power control and/or timingand/or synchronisation for a child (e.g., terminal or IAB child node) onthe communication link it provides, e.g. analogously to the approachesdescribed above. Providing a communication link may comprisetransmitting and/or receiving signaling on the link, based on thecommunication timing. The timing for transmission and reception on thecommunication may be linked, e.g. based on distance to the communicationpartner and/or timing advance or timing advance adjustment for thecommunication partner (e.g., a terminal, if it is an access link, and anIAB node if it is a backhaul link). In general, the communication timingmay be used for multiple communication links provided by the IAB node,e.g. an access link and/or one or more backhaul links. An access linkmay pertain to a cell, or more than one cell, provided by the IAB node,which may allow radio access for a plurality of terminals. A backhaullink may be device-specific, e.g. with strong beamforming to astationary child node.

It may be considered that the timing of transmission by the IAB node onthe communication link may be based on the communication timing. Thetransmission timing may be specific to the IAB node, not dependent onchild devices like terminals or IAB child nodes. In some cases, thetransmission timing may also determine the reception timing, e.g.device-specific.

In some variants, the timing of reception by the IAB node on thecommunication link is based on the communication timing. The receptiontiming may depend on the transmission timing of the transmitter, e.g. achild device like a terminal or IAB child node. This transmission timingmay be controlled by the IAB node based on the communication timing,e.g. based on control signaling, which may indicate timing advanceand/or advance adjustment, and/or based on synchronisation signalinglike SS/PBCH block signaling, which may define the basic synchronisationof a timing grid used for the communication link.

The communication timing may be based on a function of the first timingand the second timing, and/or in a function of parent timings. Thefunction may be based on a sum or weighted sum, e.g. weighted for eachlink and/or parent.

The first timing may be based on control signaling indicating timingand/or synchronisation received from the first parent node, e.g.indicating timing advance and/or timing advance adjustment, for thefirst backhaul link, and/or the second timing may be based on controlsignaling indicating timing and/or synchronisation received from thesecond parent node, e.g. indicating timing advance and/or timing advanceadjustment, for the second backhaul link. Other parent timing may beprovided similarly. Parent timing may generally indicate one or moreaspects of timing associated to communication on the associated backhaullink, e.g. timing advance and/or timing advance adjustment, and/orreception timing and/or transmission timing of the parent node, and/orreception timing and/or transmission timing of the IAB node (child node)for this backhaul link, and/or synchronisation provided by the parentnode.

The communication timing may be based on a timing synchronised relativeto a donor node. A donor node may generally be an IAB node withhigher-layer control functionality, and/or an IAB node with a cableconnection to a core network, e.g. via fibre or wire. The donor node mayprovide synchronisation via synchronisation signaling, e.g. SS/PBCHblock signaling, synchronising its child nodes, which then providesimilar synchronisation to their child nodes, etc. Each synchronisationstep may be based on the parent synchronisation, such that in general,the whole IAB arrangement connected to one donor may be similarlysynchronised. It should be noted that individual transmission andreception timing may be based on the synchronisation, but may beshifted, e.g. due to delay and/or signal travel time effects, which maybe accommodated for e.g. via timing advance and/or timing advanceadjustment functionality. Also, the synchronisation may be considered topertain to the physical layer, e.g. in regard to the timing grid used.When specific signaling is transmitted on this grid may be determined ona higher layer, e.g. by a scheduler and/or the MAC or higher layer.

The communication timing may in particular be based on a weighted sumover the first timing and the second timing. This allows considereddifferent characteristics of links.

The communication timing may be based on received power and/or signalquality, for example one or a combination of SIR, SNR, SINR, BER or BLERor energy or power per resource element or similar parameters of signalquality. The signal quality may be determined by the IAB node, e.g.based on measurements, in particular based on measurement of referencesignaling on the backhaul links.

The IAB node may be connected, or adapted to be connected orconnectable, to a plurality N of parent nodes via associated backhaullinks with corresponding timings. Thus, complex IAB node arrangementwith high levels of redundancy and/or high data throughput may beprovided.

The communication timing may in general be based on the number of parentnodes of the IAB node, and/or hop-count of a parent. The hop-number mayindicate the number of backhaul links signaling has to go over from aterminal on an access link of the IAB node to the donor. Links withlower hop-count may be weighed higher than links with higher hop-count.For example, a weight may be dependent on 1/HC, with HC the hop-count ofa link or associated to a parent. It should generally be considered thateach parent may be associated to one backhaul link to the IAB node.

The communication timing may be based on link latency and/or propagationdelay, e.g. for each link. Lower latency and/or propagation delay may beweighted higher than higher latency and/or delay. The latency and/ordelay may be measured during operation, e.g. by the IAB node, and/or maybe provided by another node, in particular a parent node.

It may be considered that the communication timing is based onhistorical information and/or numerology, e.g. relative to thenumerology used by the donor node and/or communication link provided bythe IAB, for example if it is an access link. Historical information mayprovide information regarding operational conditions over time, e.g.regarding data throughput and/or variation of signal quality or receivedpower and/or activity on access links. Such information may be stored ina memory of the IAB node, and/or be provided by higher-layerfunctionality, e.g. from the network, in particular a donor node ormanagement function, e.g. a MME.

In general, parameters on which the communication timing may be based onmay pertain to each parent or backhaul link provided by a parent. It maybe considered that a weight for a link is based on one or moreparameters, and/or a different functional correspondence may beconsidered. For example, a parabolic function instead of a weighted summay be used. A sum with all weights being 1, or being equal, may beconsidered a weighted sum. However, in at least some variants, differentlinks may be weighted differently, e.g. by assigning different weights.It may be considered that the communication timing is based on amulti-weight sum, e.g. one sum over multiple different functionsdependent on time, which may have associated different weights to them,for example in the form of a(k)*f1+b(k)*f2+c(k)*f3, wherein a, b and crepresent weight functions per link, e.g. based on different parameters,and f1, f2 and f3 represent different functions depending on parenttiming. The different functions may be dependent of different aspects ofparent timing, e.g. reception timing and/or transmission timing and/ortiming advance and/or timing advance adjustment. B(k) and/or c(k) may bezero. It may in general be considered that the dependence of thecommunication timing on parent timings is configured or configurable,e.g. via higher layer signaling from a donor node. Such signaling may ingeneral be transmitted to the IAB node via a backhaul link. For example,values of the weights to be used may be configured.

A program product comprising instructions adapted for causing processingcircuitry to control and/or perform any method described herein may beconsidered. Also, there is described a carrier medium arrangementcarrying and/or storing such a program product.

The approaches described herein allow use of a downlink timingconsidering influence from multiple parents, which is particularlysuitable for a multi-parent IAB arrangement. In particular, the timingaccommodates for different operational conditions on different linkswith different parents, and provides a stable environment, even ifcommunication is relayed or routed over different links or paths atdifferent times.

In the context of this disclosure, a backhaul link to a parent may bereferred to as UL backhaul link, a backhaul link to a child may bereferred to as DL backhaul link. For each backhaul link, there may becommunication in both directions, from parent to child and reverse.Communication on a backhaul from child to parent may be considered ULcommunication, or UL component of the backhaul link, and from parent tochild may be considered DL communication, or DL component of thebackhaul link. Thus, for an IAB node with an UL backhaul link, ULcommunication 215 goes from the IAB node to a parent node, and DLcommunication from parent to the IAB node, for this backhaul link. For aDL backhaul link, UL communication would go from the child to the IABnode, and DL communication from the IAB node to the child., for thebackhaul link. An analogous terminology may be used for an access link,providing radio access to terminals.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings are provided to illustrate concepts and approachesdescribed herein, and are not intended to limit their scope. Thedrawings comprise:

FIG. 1, showing an exemplary IAB arrangement;

FIG. 2, showing another exemplary IAB arrangement;

FIG. 3, showing a scenario with multiple IAB parents;

FIG. 4, showing a scenario with multiple IAB parents with one signalingpath;

FIG. 5, showing a scenario with multiple IAB parents with two signalingpaths;

FIG. 6, showing UL control in a multiple IAB parent scenario;

FIG. 7, showing an exemplary radio node implemented as terminal or UE;

FIG. 8, showing an exemplary radio node implemented as network node; and

FIG. 9 showing an exemplary IAB node.

DETAILED DESCRIPTION

In the following, variants are described in the context of NR, however,the approaches may be implemented in different contexts.

FIG. 1 shows an exemplary setup of a backhaul arrangement. An IAB donornode (also referred to as donor) may be connected to a core network viaa wireline connection (cable or fibre, e.g.). It provides radio accessfor terminals, and a wireless connection to another network node, an IABnode 1. The IAB node 1 also provides radio access for terminals (via anaccess link), and communicates to the donor via a wireless connectionproviding a backhaul link. Moreover, it provides a backhaul link to anIAB node 2. FIG. 1 thus shows a multi-hop arrangement, whereincommunication via IAB node 2 passes via two backhaul links until itreaches the IAB donor. In general, an IAB node may be any node that isadapted for providing radio access to one or more terminals/UEs (viaaccess links), and also may access and/or provide one or more backhaullinks. A backhaul link may generally be provided to route and/or forwardcommunication from or to a terminal to another IAB node, e.g. usingradio signaling. Backhaul and access links may in general use the sameor different resource structures. In particular, they may operate on thesame carriers and/or carrier aggregations. The carriers used may inparticular be mm-wave carriers, e.g. above 6 GHz or 20 GHz or 30 GHz infrequency. For each IAB node, each backhaul link terminated at an IABnode to be used to reach a donor may be counted as one hop. For example,an IAB node connected to a donor directly with a backhaul link wouldhave a hop-count of 1, IAB node 2 in FIG. 1 has one of 2. Formultiple-parent scenarios, different paths to a donor may have differenthop-counts, or the same, depending on the arrangement.

FIG. 2 shows a different view of an IAB arrangement. From an IAB nodespoint of view, it may be connected via a backhaul (BH) link to a parentnode, which may be closer to the donor node (or be the donor nodeitself) in terms of backhaul links needed to reach the donor. Eachbackhaul link may comprise an UL component and DL component, which mayfor example be in TDD or FDD operation. In UL, communication may betransmitted in the direction of the donor. In DL, communication may befrom the donor, e.g. to a terminal connected to the IAB node, or anotherIAB connected via another backhaul link. A device to which an IAB nodeprovides radio access, either via an access link or backhaul link, maybe considered a child node. An IAB node may in general processinformation received via an access link or backhaul link, e.g. to routeits content to a target terminal or other IAB node or donor. It may beconsidered that an IAB node (e.g., as parent node) provides anddetermines control signaling on the access and/or backhaul links itprovides. The control signaling may in particular be physical layercontrol signaling, e.g. DCI signaling, in particular for schedulingand/or power control and/or timing. Some IAB nodes, in particular adonor node, may be adapted to also provide higher-layer control, inparticular RRC layer control.

In general, it may be assumed that an IAB node is aware of its childrenand parents (IAB children and parents). In particular, it may be awareof all IAB nodes reachable via a backhaul link it provides itself (e.g.,children of children, or more distant children). It may be aware ofhigher-layer parents like grandparents, but in some cases not, as it maybe adapted to follow control signaling by its direct parent. A parent ofa parent may be considered a grandparent, a child of a child agrandchild, etc. A donor may be aware of all IAB nodes reachable viabackhaul links provided by the donor, e.g. all children. This may be dueto installation, or automatic communication between nodes when settingup.

FIG. 3 shows another scenario for an IAB arrangement. A donor D isconnected via backhaul links to two IAB nodes N1 and N2. D may beconsidered parent to N1 and N2. Another IAB node N3 may be connected toN1 and N2 via respective backhaul links, such that it may be consideredto have multiple parents. It may be assumed that propagation delays ofsignaling differ between backhaul links, such that the delays TP0, TP1,and in particular TP2 a and TP2 b may be different. It should be notedthat for a terminal connected to N3 via an access link, communicationwill suffer delay on at least two backhaul links (e.g., TP0 and TP2 a orTP1 and TP2 b). Delay on one link may also be caused by processing timeneeded by the IAB, if it processes signaling for forwarding or routingor relaying.

FIG. 4 shows an example in which communication from a terminal 10 isrouted via one path running via N3 and N1. The communication betweenterminal 10 and IAB node N3 is via an access link, and then is routedvia backhaul links between N3 and N1, and from N1 to D.

FIG. 5 shows an example in which communication from a terminal 10 isrouted via two paths, one running via N3, N1 and D, and one via N3, N2and D. It should be noted that N3 is a child to both N1 and N2, and willreceive physical layer control information from both parents N1, N2independently, pertaining to each backhaul link is participates in aschild. It should be noted that for a child with multiple parents, notall backhaul links have to be used for communicating data (e.g.,carrying data from or for a terminal), but a backhaul link may be keptin reserve, e.g. established and/or maintained and/or set to sleep oridle, temporarily. However, it may be considered that signaling for aterminal, or for different terminals, is distributed over time betweendifferent backhauls. The use of multiple parents may provide improvedreliability and/or a possible fallback. In some cases, differentbackhaul links may be used for different channels and/or communicationsand/or terminals based on reliability or quality requirements, and/orlatency requirements and/or service agreements. A connection via abackhaul link may be in RRC idle and/or in DRX and/or may be upheld byregularly providing reference signaling and/or control signaling, evenif no data signaling or signaling for or from a terminal is to becarried on the backhaul link.

FIG. 6 shows another view of a child N2 (which may be an IAB node) withmultiple parents N1 a and N1 b. There may be considered scenarios witheven more parents or changing parents. The UL communication from childN2 over the respective backhaul link to parent N1 a and N1 b will becontrolled by the respective parent, e.g. in regard to timing and powercontrol. In particular, each parent may provide the child with a timingadvance and/or timing advance correction and/or synchronisation foradjusting timing for communication using the backhaul provided by theparent. Also, each parent may provide power control (e.g., in a closedloop with TPC commands) to adjust power within its backhaul link. Thechild generally has to adapt to this control, as otherwise the receptionat the respective parent may be severely impacted, e.g. due tonon-synchronised waveforms arriving, or the UL backhaul communicationnot being received or overshadowing other signaling (e.g., terminal inaccess links to the parent) due to transmission power being too low ortoo high. The timing and power control from different parents generallymay be independent.

The downlink timing for the child node, the timing for its own backhaullink/s and/or access link/s, may in some variants not be directlycontrolled by the parent/s, e.g. due to its influencing reception ofsignaling at the parents not or to a lesser degree.

There may generally be assumed that a parent (P) node's DL transmittiming DLTx(p) is used as reference timing for a child's UL backhaullink (e.g., both for UL and DL components thereof). A child node (C) mayreceive the DL signal at DLRx(c)=DLTx(p)+Tprop, wherein Tprop is thepropagation delay between parent P and child C. Node P signals a timingadvance TA (and/or a TA adjustment information dTA) to node C todetermine its uplink transmission timing ULTx(c) as DLRx(c)-(TA+dTA),such that ULRx(p) (time of reception of UL signaling transmitted by thechild C in the UL backhaul) is received at ULRx(p)=DLTx(p)+TΔ. Node Cmay determine node P's DLTx(p) as DLTx(p)=DLRx(c)-(TA+dTA+TΔ)/2 (whichshould sum up to DLTx(p)=DLRx(c)-Tprop, assuming TA+dT=2Tprop-TΔ). Thus,the timing for the UL backhaul may be controlled by the parent.

In the following, DLRx(c,k), ULTx(c,k), TA(k), TΔ(k) may be set as DL Rxtiming, UL Tx timing, actual timing advance (e.g., difference betweenDLRx(c,k) and ULTx(c,k)) and shift of ULRx(k) relative to DLTx(k) asmeasured or received over link k between parent k and a child (havingparents k=1 . . . N). Assuming a node C has N parents, transmitting DLsignals at DLTx, the node C may determine its DLTx(c) as

$\begin{matrix}\begin{matrix}{{{DLTx}(c)} = {{su}{m_{-}\left( {1\ldots\mspace{14mu} N} \right)}{a(k)}*\left( {{{DL}R{x(k)}} - {\left( {{T{A(k)}} + {T{\Delta(k)}}} \right)/2}} \right)}} \\{= {{su}{m_{-}\left( {1\ldots\mspace{14mu} N} \right)}{a(k)}*{\left( {{{DLRx}\left( {c,k} \right)} + {{ULTx}\left( {c,k} \right)} - {T\;{\Delta(k)}}} \right)/2}}}\end{matrix} & \;\end{matrix}$

It may be considered sum_(1 . . . N) a(k)=1

a(k) may corresponds weights for different backlhaul links (UL backhaulslinks from the perspective of the child). a(k) may be function of

-   -   signal quality, e.g. SNR(k) (over link k from parent k to C);        and/or    -   received/receiving time DLRx(c,k), and/or the associated timing        advance or timing advance adjustment; and/or    -   the number of C's parents N; and/or    -   the parents' hop-count (e.g. the #hops from parent (or child) to        donor node); and/or    -   latency on link k (e.g., total latency over the path, or latency        just on the direct backhaul link); and/or    -   propagation delay Tprop on link k, and/or    -   based on history (e.g. throughput records); and/or    -   received power on link k, and/or        -   numerology on link k (which may be configured and/or            configurable).

In some variants, a(k) could be configured by one or several parentnodes, or a network function, e.g. by the donor node.

In another variant, there may be considered

DLTx(c)=sum_(1 . . . N)(a(k)*DLRx(c,k)+b(k)*ULTx(c,k)−c(k)*TΔ(k))/2

It may be considered sum_(1 . . . N) a(k)=sum_(1 . . . N) b(k)=sum_(1 .. . N) c(k)=1

a(k), b(k), c(k) may be functions of

-   -   signal quality, e.g. SNR(k) (over link k from parent k to C);        and/or    -   received/receiving time DLRx(c,k), and/or the associated timing        advance or timing advance adjustment per link; and/or    -   number of C's parents N; and/or    -   parents' hop-count (e.g., the #hops from parent (or child) to        donor node); and/or    -   latency on link k and/or on the path/s using link k; and/or    -   propagation delay Tprop on link k; and/or    -   based on history (e.g. throughput records); and/or    -   received power on link k; and/or    -   numerology on link k.

In general, weights and/or a(k), and/or b(k) and/or c(k) if used, couldbe configured by one or several parent nodes, or a network function,e.g. by the donor node. Thus, the DL timing of an IAB may thus be IABarrangement. It should be noted that a path may include all backhaullinks to be used from an IAB node to reach a donor. In a multiple-parentscenario, there may be multiple paths for any given IAB node. The DLtiming may generally be a timing applied by the IAB node to a backhauland/or access link is provides, a DL backhaul link. The timing maypertain to the DL component and/or UL component of the backhaul link oraccess link. The UL component may be subject to timing advance and/ortiming advance adjustment of the link, e.g. signaling by the IAB nodeproviding the DL backhaul link.

FIG. 7 schematically shows a radio node, in particular a terminal orwireless device 10, which may in particular be implemented as a UE (UserEquipment). Radio node 10 comprises processing circuitry (which may alsobe referred to as control circuitry) 20, which may comprise a controllerconnected to a memory. Any module of the radio node 10, e.g. acommunicating module or determining module, may be implemented in and/orexecutable by, the processing circuitry 20, in particular as module inthe controller. Radio node 10 also comprises radio circuitry 22providing receiving and transmitting or transceiving functionality(e.g., one or more transmitters and/or receivers and/or transceivers),the radio circuitry 22 being connected or connectable to the processingcircuitry. An antenna circuitry 24 of the radio node 10 is connected orconnectable to the radio circuitry 22 to collect or send and/or amplifysignals. Radio circuitry 22 and the processing circuitry 20 controllingit are configured for cellular communication with a network, e.g. a RANas described herein, and/or for sidelink communication. Radio node 10may generally be adapted to carry out any of the methods of operating aradio node like terminal or UE disclosed herein; in particular, it maycomprise corresponding circuitry, e.g. processing circuitry, and/ormodules.

FIG. 8 schematically show a radio node 100, which may in particular beimplemented as a network node 100, for example an eNB or gNB or similarfor NR. Radio node 100 comprises processing circuitry (which may also bereferred to as control circuitry) 120, which may comprise a controllerconnected to a memory. Any module, e.g. transmitting module and/orreceiving module and/or configuring module of the node 100 may beimplemented in and/or executable by the processing circuitry 120. Theprocessing circuitry 120 is connected to control radio circuitry 122 ofthe node 100, which provides receiver and transmitter and/or transceiverfunctionality (e.g., comprising one or more transmitters and/orreceivers and/or transceivers). An antenna circuitry 124 may beconnected or connectable to radio circuitry 122 for signal reception ortransmittance and/or amplification. Node 100 may be adapted to carry outany of the methods for operating a radio node or network node disclosedherein; in particular, it may comprise corresponding circuitry, e.g.processing circuitry, and/or modules. The antenna circuitry 124 may beconnected to and/or comprise an antenna array. The node 100,respectively its circuitry, may be adapted to perform any of the methodsof operating a network node or a radio node as described herein; inparticular, it may comprise corresponding circuitry, e.g. processingcircuitry, and/or modules. The radio node 100 may generally comprisecommunication circuitry, e.g. for communication with another networknode, like a radio node, and/or with a core network and/or an internetor local net, in particular with an information system, which mayprovide information and/or data to be transmitted to a user equipment.

FIG. 9 shows an exemplary IAB node 200, which may be considered a formof radio node. The IAB node may in general be adapted for providingradio access to one or more terminals or UEs, and to communicate via abackhaul link with another IAB node, e.g. by providing the backhaullink, or by using it as a child node. A donor node may be considered aform of IAB node. From an IAB node's of view, UL communication may becommunication via a backhaul link provided by a parent node 250, whichmay comprise UL and DL components itself, from and to the IAB node 200.DL communication may be communication via a backhaul link provided bythe IAB node itself, or an access link provided by the IAB node, e.g. toterminals 270, 275 or IAB (child) node 280. This DL communication mayalso have UL and DL components, to and from the IAB node 200. The IABnode may be a radio node, which may comprise radio circuitry and/orprocessing circuitry and/or antenna circuitry and/or an antennaarrangement and/or other circuitry, as described ofr radio nodes ingeneral. In particular, it may comprise circuitry 210 corresponding toterminal functionality 210 (also referred to as MT), and circuitry 220corresponding to IAB control functionality (also referred to as DU). AnIAB node that is a donor node may in some variants comprise circuitrycorresponding to higher layer functionality, which may be also referredto as CU functionality. An IAB node may be adapted to carry out and/orcontrol any of the methods described herein.

References to specific resource structures like transmission timingstructure and/or symbol and/or slot and/or mini-slot and/or subcarrierand/or carrier may pertain to a specific numerology, which may bepredefined and/or configured or configurable. A transmission timingstructure may represent a time interval, which may cover one or moresymbols. Some examples of a transmission timing structure aretransmission time interval (TTI), subframe, slot and mini-slot. A slotmay comprise a predetermined, e.g. predefined and/or configured orconfigurable, number of symbols, e.g. 6 or 7, or 12 or 14. A mini-slotmay comprise a number of symbols (which may in particular beconfigurable or configured) smaller than the number of symbols of aslot, in particular 1, 2, 3 or 4 symbols. A transmission timingstructure may cover a time interval of a specific length, which may bedependent on symbol time length and/or cyclic prefix used. Atransmission timing structure may pertain to, and/or cover, a specifictime interval in a time stream, e.g. synchronized for communication.Timing structures used and/or scheduled for transmission, e.g. slotand/or mini-slots, may be scheduled in relation to, and/or synchronizedto, a timing structure provided and/or defined by other transmissiontiming structures. Such transmission timing structures may define atiming grid, e.g., with symbol time intervals within individualstructures representing the smallest timing units. Such a timing gridmay for example be defined by slots or subframes (wherein in some cases,subframes may be considered specific variants of slots). A transmissiontiming structure may have a duration (length in time) determined basedon the durations of its symbols, possibly in addition to cyclicprefix/es used. The symbols of a transmission timing structure may havethe same duration, or may in some variants have different duration. Thenumber of symbols in a transmission timing structure may be predefinedand/or configured or configurable, and/or be dependent on numerology.The timing of a mini-slot may generally be configured or configurable,in particular by the network and/or a network node. The timing may beconfigurable to start and/or end at any symbol of the transmissiontiming structure, in particular one or more slots.

There is generally considered a program product comprising instructionsadapted for causing processing and/or control circuitry to carry outand/or control any method described herein, in particular when executedon the processing and/or control circuitry. Also, there is considered acarrier medium arrangement carrying and/or storing a program product asdescribed herein.

A carrier medium arrangement may comprise one or more carrier media.Generally, a carrier medium may be accessible and/or readable and/orreceivable by processing or control circuitry. Storing data and/or aprogram product and/or code may be seen as part of carrying data and/ora program product and/or code. A carrier medium generally may comprise aguiding/transporting medium and/or a storage medium. Aguiding/transporting medium may be adapted to carry and/or carry and/orstore signals, in particular electromagnetic signals and/or electricalsignals and/or magnetic signals and/or optical signals. A carriermedium, in particular a guiding/transporting medium, may be adapted toguide such signals to carry them. A carrier medium, in particular aguiding/transporting medium, may comprise the electromagnetic field,e.g. radio waves or microwaves, and/or optically transmissive material,e.g. glass fiber, and/or cable. A storage medium may comprise at leastone of a memory, which may be volatile or non-volatile, a buffer, acache, an optical disc, magnetic memory, flash memory, etc.

A system comprising one or more radio nodes as described herein, inparticular a network node and a user equipment, is described. The systemmay be a wireless communication system, and/or provide and/or representa radio access network.

Moreover, there may be generally considered a method of operating aninformation system, the method comprising providing information.Alternatively, or additionally, an information system adapted forproviding information may be considered. Providing information maycomprise providing information for, and/or to, a target system, whichmay comprise and/or be implemented as radio access network and/or aradio node, in particular a network node or user equipment or terminal.Providing information may comprise transferring and/or streaming and/orsending and/or passing on the information, and/or offering theinformation for such and/or for download, and/or triggering suchproviding, e.g. by triggering a different system or node to streamand/or transfer and/or send and/or pass on the information. Theinformation system may comprise, and/or be connected or connectable to,a target, for example via one or more intermediate systems, e.g. a corenetwork and/or internet and/or private or local network. Information maybe provided utilising and/or via such intermediate system/s. Providinginformation may be for radio transmission and/or for transmission via anair interface and/or utilising a RAN or radio node as described herein.Connecting the information system to a target, and/or providinginformation, may be based on a target indication, and/or adaptive to atarget indication. A target indication may indicate the target, and/orone or more parameters of transmission pertaining to the target and/orthe paths or connections over which the information is provided to thetarget. Such parameter/s may in particular pertain to the air interfaceand/or radio access network and/or radio node and/or network node.Example parameters may indicate for example type and/or nature of thetarget, and/or transmission capacity (e.g., data rate) and/or latencyand/or reliability and/or cost, respectively one or more estimatesthereof. The target indication may be provided by the target, ordetermined by the information system, e.g. based on information receivedfrom the target and/or historical information, and/or be provided by auser, for example a user operating the target or a device incommunication with the target, e.g. via the RAN and/or air interface.For example, a user may indicate on a user equipment communicating withthe information system that information is to be provided via a RAN,e.g. by selecting from a selection provided by the information system,for example on a user application or user interface, which may be a webinterface. An information system may comprise one or more informationnodes. An information node may generally comprise processing circuitryand/or communication circuitry. In particular, an information systemand/or an information node may be implemented as a computer and/or acomputer arrangement, e.g. a host computer or host computer arrangementand/or server or server arrangement. In some variants, an interactionserver (e.g., web server) of the information system may provide a userinterface, and based on user input may trigger transmitting and/orstreaming information provision to the user (and/or the target) fromanother server, which may be connected or connectable to the interactionserver and/or be part of the information system or be connected orconnectable thereto. The information may be any kind of data, inparticular data intended for a user of for use at a terminal, e.g. videodata and/or audio data and/or location data and/or interactive dataand/or game-related data and/or environmental data and/or technical dataand/or traffic data and/or vehicular data and/or circumstantial dataand/or operational data. The information provided by the informationsystem may be mapped to, and/or mappable to, and/or be intended formapping to, communication or data signaling and/or one or more datachannels as described herein (which may be signaling or channel/s of anair interface and/or used within a RAN and/or for radio transmission).It may be considered that the information is formatted based on thetarget indication and/or target, e.g. regarding data amount and/or datarate and/or data structure and/or timing, which in particular may bepertaining to a mapping to communication or data signaling and/or a datachannels. Mapping information to data signaling and/or data channel/smay be considered to refer to using the signaling/channel/s to carry thedata, e.g. on higher layers of communication, with thesignaling/channel/s underlying the transmission. A target indicationgenerally may comprise different components, which may have differentsources, and/or which may indicate different characteristics of thetarget and/or communication path/s thereto. A format of information maybe specifically selected, e.g. from a set of different formats, forinformation to be transmitted on an air interface and/or by a RAN asdescribed herein. This may be particularly pertinent since an airinterface may be limited in terms of capacity and/or of predictability,and/or potentially be cost sensitive. The format may be selected to beadapted to the transmission indication, which may in particular indicatethat a RAN or radio node as described herein is in the path (which maybe the indicated and/or planned and/or expected path) of informationbetween the target and the information system. A (communication) path ofinformation may represent the interface/s (e.g., air and/or cableinterfaces) and/or the intermediate system/s (if any), between theinformation system and/or the node providing or transferring theinformation, and the target, over which the information is, or is to be,passed on. A path may be (at least partly) undetermined when a targetindication is provided, and/or the information is provided/transferredby the information system, e.g. if an internet is involved, which maycomprise multiple, dynamically chosen paths. Information and/or a formatused for information may be packet-based, and/or be mapped, and/or bemappable and/or be intended for mapping, to packets. Alternatively, oradditionally, there may be considered a method for operating a targetdevice comprising providing a target indicating to an informationsystem. More alternatively, or additionally, a target device may beconsidered, the target device being adapted for providing a targetindication to an information system. In another approach, there may beconsidered a target indication tool adapted for, and/or comprising anindication module for, providing a target indication to an informationsystem. The target device may generally be a target as described above.A target indication tool may comprise, and/or be implemented as,software and/or application or app, and/or web interface or userinterface, and/or may comprise one or more modules for implementingactions performed and/or controlled by the tool. The tool and/or targetdevice may be adapted for, and/or the method may comprise, receiving auser input, based on which a target indicating may be determined and/orprovided. Alternatively, or additionally, the tool and/or target devicemay be adapted for, and/or the method may comprise, receivinginformation and/or communication signaling carrying information, and/oroperating on, and/or presenting (e.g., on a screen and/or as audio or asother form of indication), information. The information may be based onreceived information and/or communication signaling carryinginformation. Presenting information may comprise processing receivedinformation, e.g. decoding and/or transforming, in particular betweendifferent formats, and/or for hardware used for presenting. Operating oninformation may be independent of or without presenting, and/or proceedor succeed presenting, and/or may be without user interaction or evenuser reception, for example for automatic processes, or target deviceswithout (e.g., regular) user interaction like MTC devices, of forautomotive or transport or industrial use. The information orcommunication signaling may be expected and/or received based on thetarget indication. Presenting and/or operating on information maygenerally comprise one or more processing steps, in particular decodingand/or executing and/or interpreting and/or transforming information.Operating on information may generally comprise relaying and/ortransmitting the information, e.g. on an air interface, which mayinclude mapping the information onto signaling (such mapping maygenerally pertain to one or more layers, e.g. one or more layers of anair interface, e.g. RLC (Radio Link Control) layer and/or MAC layerand/or physical layer/s). The information may be imprinted (or mapped)on communication signaling based on the target indication, which maymake it particularly suitable for use in a RAN (e.g., for a targetdevice like a network node or in particular a UE or terminal). The toolmay generally be adapted for use on a target device, like a UE orterminal. Generally, the tool may provide multiple functionalities, e.g.for providing and/or selecting the target indication, and/or presenting,e.g. video and/or audio, and/or operating on and/or storing receivedinformation. Providing a target indication may comprise transmitting ortransferring the indication as signaling, and/or carried on signaling,in a RAN, for example if the target device is a UE, or the tool for aUE. It should be noted that such provided information may be transferredto the information system via one or more additionally communicationinterfaces and/or paths and/or connections. The target indication may bea higher-layer indication and/or the information provided by theinformation system may be higher-layer information, e.g. applicationlayer or user-layer, in particular above radio layers like transportlayer and physical layer. The target indication may be mapped onphysical layer radio signaling, e.g. related to or on the user-plane,and/or the information may be mapped on physical layer radiocommunication signaling, e.g. related to or on the user-plane (inparticular, in reverse communication directions). The describedapproaches allow a target indication to be provided, facilitatinginformation to be provided in a specific format particularly suitableand/or adapted to efficiently use an air interface. A user input may forexample represent a selection from a plurality of possible transmissionmodes or formats, and/or paths, e.g. in terms of data rate and/orpackaging and/or size of information to be provided by the informationsystem.

In general, a numerology and/or subcarrier spacing may indicate thebandwidth (in frequency domain) of a subcarrier of a carrier, and/or thenumber of subcarriers in a carrier and/or the numbering of thesubcarriers in a carrier. Different numerologies may in particular bedifferent in the bandwidth of a subcarrier. In some variants, all thesubcarriers in a carrier have the same bandwidth associated to them. Thenumerology and/or subcarrier spacing may be different between carriersin particular regarding the subcarrier bandwidth. A symbol time length,and/or a time length of a timing structure pertaining to a carrier maybe dependent on the carrier frequency, and/or the subcarrier spacingand/or the numerology. In particular, different numerologies may havedifferent symbol time lengths.

Signaling may generally comprise one or more symbols and/or signalsand/or messages. A signal may comprise or represent one or more bits. Anindication may represent signaling, and/or be implemented as a signal,or as a plurality of signals. One or more signals may be included inand/or represented by a message. Signaling, in particular controlsignaling, may comprise a plurality of signals and/or messages, whichmay be transmitted on different carriers and/or be associated todifferent signaling processes, e.g. representing and/or pertaining toone or more such processes and/or corresponding information. Anindication may comprise signaling, and/or a plurality of signals and/ormessages and/or may be comprised therein, which may be transmitted ondifferent carriers and/or be associated to different acknowledgementsignaling processes, e.g. representing and/or pertaining to one or moresuch processes. Signaling associated to a channel may be transmittedsuch that represents signaling and/or information for that channel,and/or that the signaling is interpreted by the transmitter and/orreceiver to belong to that channel. Such signaling may generally complywith transmission parameters and/or format/s for the channel.

Reference signaling may be signaling comprising one or more referencesymbols and/or structures. Reference signaling may be adapted forgauging and/or estimating and/or representing transmission conditions,e.g. channel conditions and/or transmission path conditions and/orchannel (or signal or transmission) quality. It may be considered thatthe transmission characteristics (e.g., signal strength and/or formand/or modulation and/or timing) of reference signaling are availablefor both transmitter and receiver of the signaling (e.g., due to beingpredefined and/or configured or configurable and/or being communicated).Different types of reference signaling may be considered, e.g.pertaining to uplink, downlink or sidelink, cell-specific (inparticular, cell-wide, e.g., CRS) or device or user specific (addressedto a specific target or user equipment, e.g., CSI-RS),demodulation-related (e.g., DMRS) and/or signal strength related, e.g.power-related or energy-related or amplitude-related (e.g., SRS or pilotsignaling) and/or phase-related, etc.

An antenna arrangement may comprise one or more antenna elements(radiating elements), which may be combined in antenna arrays. Anantenna array or subarray may comprise one antenna element, or aplurality of antenna elements, which may be arranged e.g. twodimensionally (for example, a panel) or three dimensionally. It may beconsidered that each antenna array or subarray or element is separatelycontrollable, respectively that different antenna arrays arecontrollable separately from each other. A single antennaelement/radiator may be considered the smallest example of a subarray.Examples of antenna arrays comprise one or more multi-antenna panels orone or more individually controllable antenna elements. An antennaarrangement may comprise a plurality of antenna arrays. It may beconsidered that an antenna arrangement is associated to a (specificand/or single) radio node, e.g. a configuring or informing or schedulingradio node, e.g. to be controlled or controllable by the radio node. Anantenna arrangement associated to a UE or terminal may be smaller (e.g.,in size and/or number of antenna elements or arrays) than the antennaarrangement associated to a network node. Antenna elements of an antennaarrangement may be configurable for different arrays, e.g. to change thebeam forming characteristics. In particular, antenna arrays may beformed by combining one or more independently or separately controllableantenna elements or subarrays. The beams may be provided by analogbeamforming, or in some variants by digital beamforming. The informingradio nodes may be configured with the manner of beam transmission, e.g.by transmitting a corresponding indicator or indication, for example asbeam identify indication. However, there may be considered cases inwhich the informing radio node/s are not configured with suchinformation, and/or operate transparently, not knowing the way ofbeamforming used. An antenna arrangement may be considered separatelycontrollable in regard to the phase and/or amplitude/power and/or gainof a signal feed to it for transmission, and/or separately controllableantenna arrangements may comprise an independent or separate transmitand/or receive unit and/or ADC (Analog-Digital-Converter, alternativelyan ADC chain) to convert digital control information into an analogantenna feed for the whole antenna arrangement (the ADC may beconsidered part of, and/or connected or connectable to, antennacircuitry). A scenario in which each antenna element is individuallycontrollable may be referred to as digital beamforming, whereas ascenario in which larger arrays/subarrays are separately controllablemay be considered an example of analog beamforming. Hybrid forms may beconsidered.

Uplink or sidelink signaling may be OFDMA (Orthogonal Frequency DivisionMultiple Access) or SC-FDMA (Single Carrier Frequency Division MultipleAccess) signaling. Downlink signaling may in particular be OFDMAsignaling. However, signaling is not limited thereto (Filter-Bank basedsignaling may be considered one alternative).

A radio node may generally be considered a device or node adapted forwireless and/or radio (and/or microwave) frequency communication, and/orfor communication utilising an air interface, e.g. according to acommunication standard.

A radio node may be a network node, or a user equipment or terminal. Anetwork node may be any radio node of a wireless communication network,e.g. a base station and/or gNodeB (gNB) and/or eNodeB (eNB) and/or relaynode and/or micro/nano/pico/femto node and/or transmission point (TP)and/or access point (AP) and/or other node, in particular for a RAN asdescribed herein.

The terms wireless device, user equipment (UE) and terminal may beconsidered to be interchangeable in the context of this disclosure. Awireless device, user equipment or terminal may represent an end devicefor communication utilising the wireless communication network, and/orbe implemented as a user equipment according to a standard. Examples ofuser equipments may comprise a phone like a smartphone, a personalcommunication device, a mobile phone or terminal, a computer, inparticular laptop, a sensor or machine with radio capability (and/oradapted for the air interface), in particular for MTC(Machine-Type-Communication, sometimes also referred to M2M,Machine-To-Machine), or a vehicle adapted for wireless communication. Auser equipment or terminal may be mobile or stationary.

A radio node may generally comprise processing circuitry and/or radiocircuitry. A radio node, in particular a network node, may in some casescomprise cable circuitry and/or communication circuitry, with which itmay be connected or connectable to another radio node and/or a corenetwork.

Circuitry may comprise integrated circuitry. Processing circuitry maycomprise one or more processors and/or controllers (e.g.,microcontrollers), and/or ASICs (Application Specific IntegratedCircuitry) and/or FPGAs (Field Programmable Gate Array), or similar. Itmay be considered that processing circuitry comprises, and/or is(operatively) connected or connectable to one or more memories or memoryarrangements. A memory arrangement may comprise one or more memories. Amemory may be adapted to store digital information. Examples formemories comprise volatile and non-volatile memory, and/or Random AccessMemory (RAM), and/or Read-Only-Memory (ROM), and/or magnetic and/oroptical memory, and/or flash memory, and/or hard disk memory, and/orEPROM or EEPROM (Erasable Programmable ROM or Electrically ErasableProgrammable ROM).

Radio circuitry may comprise one or more transmitters and/or receiversand/or transceivers (a transceiver may operate or be operable astransmitter and receiver, and/or may comprise joint or separatedcircuitry for receiving and transmitting, e.g. in one package orhousing), and/or may comprise one or more amplifiers and/or oscillatorsand/or filters, and/or may comprise, and/or be connected or connectableto antenna circuitry and/or one or more antennas and/or antenna arrays.An antenna array may comprise one or more antennas, which may bearranged in a dimensional array, e.g. 2D or 3D array, and/or antennapanels. A remote radio head (RRH) may be considered as an example of anantenna array. However, in some variants, a RRH may be also beimplemented as a network node, depending on the kind of circuitry and/orfunctionality implemented therein.

Communication circuitry may comprise radio circuitry and/or cablecircuitry. Communication circuitry generally may comprise one or moreinterfaces, which may be air interface/s and/or cable interface/s and/oroptical interface/s, e.g. laser-based. Interface/s may be in particularpacket-based. Cable circuitry and/or a cable interfaces may comprise,and/or be connected or connectable to, one or more cables (e.g., opticalfiber-based and/or wire-based), which may be directly or indirectly(e.g., via one or more intermediate systems and/or interfaces) beconnected or connectable to a target, e.g. controlled by communicationcircuitry and/or processing circuitry.

Any one or all of the modules disclosed herein may be implemented insoftware and/or firmware and/or hardware. Different modules may beassociated to different components of a radio node, e.g. differentcircuitries or different parts of a circuitry. It may be considered thata module is distributed over different components and/or circuitries. Aprogram product as described herein may comprise the modules related toa device on which the program product is intended (e.g., a userequipment or network node) to be executed (the execution may beperformed on, and/or controlled by the associated circuitry).

A radio access network may be a wireless communication network, and/or aRadio Access Network (RAN) in particular according to a communicationstandard. A communication standard may in particular a standardaccording to 3GPP and/or 5G, e.g. according to NR or LTE, in particularLTE Evolution.

A wireless communication network may be and/or comprise a Radio AccessNetwork (RAN), which may be and/or comprise any kind of cellular and/orwireless radio network, which may be connected or connectable to a corenetwork. The approaches described herein are particularly suitable for a5G network, e.g. LTE Evolution and/or NR (New Radio), respectivelysuccessors thereof. A RAN may comprise one or more network nodes, and/orone or more terminals, and/or one or more radio nodes. A network nodemay in particular be a radio node adapted for radio and/or wirelessand/or cellular communication with one or more terminals. A terminal maybe any device adapted for radio and/or wireless and/or cellularcommunication with or within a RAN, e.g. a user equipment (UE) or mobilephone or smartphone or computing device or vehicular communicationdevice or device for machine-type-communication (MTC), etc. A terminalmay be mobile, or in some cases stationary. A RAN or a wirelesscommunication network may comprise at least one network node and a UE,or at least two radio nodes. There may be generally considered awireless communication network or system, e.g. a RAN or RAN system,comprising at least one radio node, and/or at least one network node andat least one terminal.

Transmitting in downlink may pertain to transmission from the network ornetwork node to the terminal. Transmitting in uplink may pertain totransmission from the terminal to the network or network node.Transmitting in sidelink may pertain to (direct) transmission from oneterminal to another. Uplink, downlink and sidelink (e.g., sidelinktransmission and reception) may be considered communication directions.In some variants, uplink and downlink may also be used to describedwireless communication between network nodes, e.g. for wireless backhauland/or relay communication and/or (wireless) network communication forexample between base stations or similar network nodes, in particularcommunication terminating at such. It may be considered that backhauland/or relay communication and/or network communication is implementedas a form of sidelink or uplink communication or similar thereto.

Control information or a control information message or correspondingsignaling (control signaling) may be transmitted on a control channel,e.g. a physical control channel, which may be a downlink channel or (ora sidelink channel in some cases, e.g. one UE scheduling another UE).For example, control information/allocation information may be signaledby a network node on PDCCH (Physical Downlink Control Channel) and/or aPDSCH (Physical Downlink Shared Channel) and/or a HARQ-specific channel.Acknowledgement signaling, e.g. as a form of control information orsignaling like uplink control information/signaling, may be transmittedby a terminal on a PUCCH (Physical Uplink Control Channel) and/or PUSCH(Physical Uplink Shared Channel) and/or a HARQ-specific channel.Multiple channels may apply for multi-component/multi-carrier indicationor signaling.

Signaling may generally be considered to represent an electromagneticwave structure (e.g., over a time interval and frequency interval),which is intended to convey information to at least one specific orgeneric (e.g., anyone who might pick up the signaling) target. A processof signaling may comprise transmitting the signaling. Transmittingsignaling, in particular control signaling or communication signaling,e.g. comprising or representing acknowledgement signaling and/orresource requesting information, may comprise encoding and/ormodulating. Encoding and/or modulating may comprise error detectioncoding and/or forward error correction encoding and/or scrambling.Receiving control signaling may comprise corresponding decoding and/ordemodulation. Error detection coding may comprise, and/or be based on,parity or checksum approaches, e.g. CRC (Cyclic Redundancy Check).Forward error correction coding may comprise and/or be based on forexample turbo coding and/or Reed-Muller coding, and/or polar codingand/or LDPC coding (Low Density Parity Check). The type of coding usedmay be based on the channel (e.g., physical channel) the coded signal isassociated to. A code rate may represent the ratio of the number ofinformation bits before encoding to the number of encoded bits afterencoding, considering that encoding adds coding bits for error detectioncoding and forward error correction. Coded bits may refer to informationbits (also called systematic bits) plus coding bits.

Communication signaling may comprise, and/or represent, and/or beimplemented as, data signaling, and/or user plane signaling.Communication signaling may be associated to a data channel, e.g. aphysical downlink channel or physical uplink channel or physicalsidelink channel, in particular a PDSCH (Physical Downlink SharedChannel) or PSSCH (Physical Sidelink Shared Channel). Generally, a datachannel may be a shared channel or a dedicated channel. Data signalingmay be signaling associated to and/or on a data channel.

An indication generally may explicitly and/or implicitly indicate theinformation it represents and/or indicates. Implicit indication may forexample be based on position and/or resource used for transmission.Explicit indication may for example be based on a parametrisation withone or more parameters, and/or one or more index or indices, and/or oneor more bit patterns representing the information. It may in particularbe considered that control signaling as described herein, based on theutilised resource sequence, implicitly indicates the control signalingtype.

A resource element may generally describe the smallest individuallyusable and/or encodable and/or decodable and/or modulatable and/ordemodulatable time-frequency resource, and/or may describe atime-frequency resource covering a symbol time length in time and asubcarrier in frequency. A signal may be allocatable and/or allocated toa resource element. A subcarrier may be a subband of a carrier, e.g. asdefined by a standard. A carrier may define a frequency and/or frequencyband for transmission and/or reception. In some variants, a signal(jointly encoded/modulated) may cover more than one resource elements. Aresource element may generally be as defined by a correspondingstandard, e.g. NR or LTE. As symbol time length and/or subcarrierspacing (and/or numerology) may be different between different symbolsand/or subcarriers, different resource elements may have differentextension (length/width) in time and/or frequency domain, in particularresource elements pertaining to different carriers.

A resource generally may represent a time-frequency and/or coderesource, on which signaling, e.g. according to a specific format, maybe communicated, for example transmitted and/or received, and/or beintended for transmission and/or reception.

A border symbol may generally represent a starting symbol or an endingsymbol for transmitting and/or receiving. A starting symbol may inparticular be a starting symbol of uplink or sidelink signaling, forexample control signaling or data signaling. Such signaling may be on adata channel or control channel, e.g. a physical channel, in particulara physical uplink shared channel (like PUSCH) or a sidelink data orshared channel, or a physical uplink control channel (like PUCCH) or asidelink control channel. If the starting symbol is associated tocontrol signaling (e.g., on a control channel), the control signalingmay be in response to received signaling (in sidelink or downlink), e.g.representing acknowledgement signaling associated thereto, which may beHARQ or ARQ signaling. An ending symbol may represent an ending symbol(in time) of downlink or sidelink transmission or signaling, which maybe intended or scheduled for the radio node or user equipment. Suchdownlink signaling may in particular be data signaling, e.g. on aphysical downlink channel like a shared channel, e.g. a PDSCH (PhysicalDownlink Shared Channel). A starting symbol may be determined based on,and/or in relation to, such an ending symbol.

Configuring a radio node, in particular a terminal or user equipment,may refer to the radio node being adapted or caused or set and/orinstructed to operate according to the configuration. Configuring may bedone by another device, e.g., a network node (for example, a radio nodeof the network like a base station or eNodeB) or network, in which caseit may comprise transmitting configuration data to the radio node to beconfigured. Such configuration data may represent the configuration tobe configured and/or comprise one or more instruction pertaining to aconfiguration, e.g. a configuration for transmitting and/or receiving onallocated resources, in particular frequency resources. A radio node mayconfigure itself, e.g., based on configuration data received from anetwork or network node. A network node may utilise, and/or be adaptedto utilise, its circuitry/ies for configuring. Allocation informationmay be considered a form of configuration data. Configuration data maycomprise and/or be represented by configuration information, and/or oneor more corresponding indications and/or message/s

Generally, configuring may include determining configuration datarepresenting the configuration and providing, e.g. transmitting, it toone or more other nodes (parallel and/or sequentially), which maytransmit it further to the radio node (or another node, which may berepeated until it reaches the wireless device). Alternatively, oradditionally, configuring a radio node, e.g., by a network node or otherdevice, may include receiving configuration data and/or data pertainingto configuration data, e.g., from another node like a network node,which may be a higher-level node of the network, and/or transmittingreceived configuration data to the radio node. Accordingly, determininga configuration and transmitting the configuration data to the radionode may be performed by different network nodes or entities, which maybe able to communicate via a suitable interface, e.g., an X2 interfacein the case of LTE or a corresponding interface for NR. Configuring aterminal may comprise scheduling downlink and/or uplink transmissionsfor the terminal, e.g. downlink data and/or downlink control signalingand/or DCI and/or uplink control or data or communication signaling, inparticular acknowledgement signaling, and/or configuring resourcesand/or a resource pool therefor.

A resource structure may be considered to be neighbored in frequencydomain by another resource structure, if they share a common borderfrequency, e.g. one as an upper frequency border and the other as alower frequency border. Such a border may for example be represented bythe upper end of a bandwidth assigned to a subcarrier n, which alsorepresents the lower end of a bandwidth assigned to a subcarrier n+1. Aresource structure may be considered to be neighbored in time domain byanother resource structure, if they share a common border time, e.g. oneas an upper (or right in the figures) border and the other as a lower(or left in the figures) border. Such a border may for example berepresented by the end of the symbol time interval assigned to a symboln, which also represents the beginning of a symbol time intervalassigned to a symbol n+1.

Generally, a resource structure being neighbored by another resourcestructure in a domain may also be referred to as abutting and/orbordering the other resource structure in the domain.

A resource structure may general represent a structure in time and/orfrequency domain, in particular representing a time interval and afrequency interval. A resource structure may comprise and/or becomprised of resource elements, and/or the time interval of a resourcestructure may comprise and/or be comprised of symbol time interval/s,and/or the frequency interval of a resource structure may compriseand/or be comprised of subcarrier/s. A resource element may beconsidered an example for a resource structure, a slot or mini-slot or aPhysical Resource Block (PRB) or parts thereof may be considered others.A resource structure may be associated to a specific channel, e.g. aPUSCH or PUCCH, in particular resource structure smaller than a slot orPRB.

Examples of a resource structure in frequency domain comprise abandwidth or band, or a bandwidth part. A bandwidth part may be a partof a bandwidth available for a radio node for communicating, e.g. due tocircuitry and/or configuration and/or regulations and/or a standard. Abandwidth part may be configured or configurable to a radio node. Insome variants, a bandwidth part may be the part of a bandwidth used forcommunicating, e.g. transmitting and/or receiving, by a radio node. Thebandwidth part may be smaller than the bandwidth (which may be a devicebandwidth defined by the circuitry/configuration of a device, and/or asystem bandwidth, e.g. available for a RAN). It may be considered that abandwidth part comprises one or more resource blocks or resource blockgroups, in particular one or more PRBs or PRB groups. A bandwidth partmay pertain to, and/or comprise, one or more carriers.

A carrier may generally represent a frequency range or band and/orpertain to a central frequency and an associated frequency interval. Itmay be considered that a carrier comprises a plurality of subcarriers. Acarrier may have assigned to it a central frequency or center frequencyinterval, e.g. represented by one or more subcarriers (to eachsubcarrier there may be generally assigned a frequency bandwidth orinterval). Different carriers may be non-overlapping, and/or may beneighboring in frequency domain.

It should be noted that the term “radio” in this disclosure may beconsidered to pertain to wireless communication in general, and may alsoinclude wireless communication utilising microwave and/or millimeterand/or other frequencies, in particular between 100 MHz or 1 GHz, and100 GHz or 20 or 10 GHz. Such communication may utilise one or morecarriers.

A radio node, in particular a network node or a terminal, may generallybe any device adapted for transmitting and/or receiving radio and/orwireless signals and/or data, in particular communication data, inparticular on at least one carrier. The at least one carrier maycomprise a carrier accessed based on a LBT procedure (which may becalled LBT carrier), e.g., an unlicensed carrier. It may be consideredthat the carrier is part of a carrier aggregate.

Receiving or transmitting on a cell or carrier may refer to receiving ortransmitting utilizing a frequency (band) or spectrum associated to thecell or carrier. A cell may generally comprise and/or be defined by orfor one or more carriers, in particular at least one carrier for ULcommunication/transmission (called UL carrier) and at least one carrierfor DL communication/transmission (called DL carrier). It may beconsidered that a cell comprises different numbers of UL carriers and DLcarriers. Alternatively, or additionally, a cell may comprise at leastone carrier for UL communication/transmission and DLcommunication/transmission, e.g., in TDD-based approaches.

A channel may generally be a logical, transport or physical channel. Achannel may comprise and/or be arranged on one or more carriers, inparticular a plurality of subcarriers. A channel carrying and/or forcarrying control signaling/control information may be considered acontrol channel, in particular if it is a physical layer channel and/orif it carries control plane information. Analogously, a channel carryingand/or for carrying data signaling/user information may be considered adata channel, in particular if it is a physical layer channel and/or ifit carries user plane information. A channel may be defined for aspecific communication direction, or for two complementary communicationdirections (e.g., UL and DL, or sidelink in two directions), in whichcase it may be considered to have two component channels, one for eachdirection. Examples of channels comprise a channel for low latencyand/or high reliability transmission, in particular a channel forUltra-Reliable Low Latency Communication (URLLC), which may be forcontrol and/or data.

In general, a symbol may represent and/or be associated to a symbol timelength, which may be dependent on the carrier and/or subcarrier spacingand/or numerology of the associated carrier. Accordingly, a symbol maybe considered to indicate a time interval having a symbol time length inrelation to frequency domain. A symbol time length may be dependent on acarrier frequency and/or bandwidth and/or numerology and/or subcarrierspacing of, or associated to, a symbol. Accordingly, different symbolsmay have different symbol time lengths. In particular, numerologies withdifferent subcarrier spacings may have different symbol time length.Generally, a symbol time length may be based on, and/or include, a guardtime interval or cyclic extension, e.g. prefix or postfix.

Communication or communicating may generally comprise transmittingand/or receiving signaling. Communication on a sidelink (or sidelinksignaling) may comprise utilising the sidelink for communication(respectively, for signaling). Sidelink transmission and/or transmittingon a sidelink may be considered to comprise transmission utilising thesidelink, e.g. associated resources and/or transmission formats and/orcircuitry and/or the air interface. Sidelink reception and/or receivingon a sidelink may be considered to comprise reception utilising thesidelink, e.g. associated resources and/or transmission formats and/orcircuitry and/or the air interface. Sidelink control information (e.g.,SCI) may generally be considered to comprise control informationtransmitted utilising a sidelink.

Generally, carrier aggregation (CA) may refer to the concept of a radioconnection and/or communication link between a wireless and/or cellularcommunication network and/or network node and a terminal or on asidelink comprising a plurality of carriers for at least one directionof transmission (e.g. DL and/or UL), as well as to the aggregate ofcarriers. A corresponding communication link may be referred to ascarrier aggregated communication link or CA communication link; carriersin a carrier aggregate may be referred to as component carriers (CC). Insuch a link, data may be transmitted over more than one of the carriersand/or all the carriers of the carrier aggregation (the aggregate ofcarriers). A carrier aggregation may comprise one (or more) dedicatedcontrol carriers and/or primary carriers (which may e.g. be referred toas primary component carrier or PCC), over which control information maybe transmitted, wherein the control information may refer to the primarycarrier and other carriers, which may be referred to as secondarycarriers (or secondary component carrier, SCC). However, in someapproaches, control information may be send over more than one carrierof an aggregate, e.g. one or more PCCs and one PCC and one or more SCCs.

A transmission may generally pertain to a specific channel and/orspecific resources, in particular with a starting symbol and endingsymbol in time, covering the interval therebetween. A scheduledtransmission may be a transmission scheduled and/or expected and/or forwhich resources are scheduled or provided or reserved. However, notevery scheduled transmission has to be realized. For example, ascheduled downlink transmission may not be received, or a scheduleduplink transmission may not be transmitted due to power limitations, orother influences (e.g., a channel on an unlicensed carrier beingoccupied). A transmission may be scheduled for a transmission timingsubstructure (e.g., a mini-slot, and/or covering only a part of atransmission timing structure) within a transmission timing structurelike a slot. A border symbol may be indicative of a symbol in thetransmission timing structure at which the transmission starts or ends.

Predefined in the context of this disclosure may refer to the relatedinformation being defined for example in a standard, and/or beingavailable without specific configuration from a network or network node,e.g. stored in memory, for example independent of being configured.Configured or configurable may be considered to pertain to thecorresponding information being set/configured, e.g. by the network or anetwork node.

A configuration or schedule, like a mini-slot configuration and/orstructure configuration, may schedule transmissions, e.g. for thetime/transmissions it is valid, and/or transmissions may be scheduled byseparate signaling or separate configuration, e.g. separate RRCsignaling and/or downlink control information signaling. Thetransmission/s scheduled may represent signaling to be transmitted bythe device for which it is scheduled, or signaling to be received by thedevice for which it is scheduled, depending on which side of acommunication the device is. It should be noted that downlink controlinformation or specifically DCI signaling may be considered physicallayer signaling, in contrast to higher layer signaling like MAC (MediumAccess Control) signaling or RRC layer signaling. The higher the layerof signaling is, the less frequent/the more time/resource consuming itmay be considered, at least partially due to the information containedin such signaling having to be passed on through several layers, eachlayer requiring processing and handling.

A scheduled transmission, and/or transmission timing structure like amini-slot or slot, may pertain to a specific channel, in particular aphysical uplink shared channel, a physical uplink control channel, or aphysical downlink shared channel, e.g. PUSCH, PUCCH or PDSCH, and/or maypertain to a specific cell and/or carrier aggregation. A correspondingconfiguration, e.g. scheduling configuration or symbol configuration maypertain to such channel, cell and/or carrier aggregation. It may beconsidered that the scheduled transmission represents transmission on aphysical channel, in particular a shared physical channel, for example aphysical uplink shared channel or physical downlink shared channel. Forsuch channels, semi-persistent configuring may be particularly suitable.

Generally, a configuration may be a configuration indicating timing,and/or be represented or configured with corresponding configurationdata. A configuration may be embedded in, and/or comprised in, a messageor configuration or corresponding data, which may indicate and/orschedule resources, in particular semi-persistently and/orsemi-statically.

A control region of a transmission timing structure may be an intervalin time for intended or scheduled or reserved for control signaling, inparticular downlink control signaling, and/or for a specific controlchannel, e.g. a physical downlink control channel like PDCCH. Theinterval may comprise, and/or consist of, a number of symbols in time,which may be configured or configurable, e.g. by (UE-specific) dedicatedsignaling (which may be single-cast, for example addressed to orintended for a specific UE), e.g. on a PDCCH, or RRC signaling, or on amulticast or broadcast channel. In general, the transmission timingstructure may comprise a control region covering a configurable numberof symbols. It may be considered that in general the border symbol isconfigured to be after the control region in time.

The duration of a symbol (symbol time length or interval) of thetransmission timing structure may generally be dependent on a numerologyand/or carrier, wherein the numerology and/or carrier may beconfigurable. The numerology may be the numerology to be used for thescheduled transmission.

Scheduling a device, or for a device, and/or related transmission orsignaling, may be considered comprising, or being a form of, configuringthe device with resources, and/or of indicating to the device resources,e.g. to use for communicating. Scheduling may in particular pertain to atransmission timing structure, or a substructure thereof (e.g., a slotor a mini-slot, which may be considered a substructure of a slot). Itmay be considered that a border symbol may be identified and/ordetermined in relation to the transmission timing structure even if fora substructure being scheduled, e.g. if an underlying timing grid isdefined based on the transmission timing structure. Signaling indicatingscheduling may comprise corresponding scheduling information and/or beconsidered to represent or contain configuration data indicating thescheduled transmission and/or comprising scheduling information. Suchconfiguration data or signaling may be considered a resourceconfiguration or scheduling configuration. It should be noted that sucha configuration (in particular as single message) in some cases may notbe complete without other configuration data, e.g. configured with othersignaling, e.g. higher layer signaling. In particular, the symbolconfiguration may be provided in addition to scheduling/resourceconfiguration to identify exactly which symbols are assigned to ascheduled transmission. A scheduling (or resource) configuration mayindicate transmission timing structure/s and/or resource amount (e.g.,in number of symbols or length in time) for a scheduled transmission.

A scheduled transmission may be transmission scheduled, e.g. by thenetwork or network node. Transmission may in this context may be uplink(UL) or downlink (DL) or sidelink (SL) transmission. A device, e.g. auser equipment, for which the scheduled transmission is scheduled, mayaccordingly be scheduled to receive (e.g., in DL or SL), or to transmit(e.g. in UL or SL) the scheduled transmission. Scheduling transmissionmay in particular be considered to comprise configuring a scheduleddevice with resource/s for this transmission, and/or informing thedevice that the transmission is intended and/or scheduled for someresources. A transmission may be scheduled to cover a time interval, inparticular a successive number of symbols, which may form a continuousinterval in time between (and including) a starting symbol and an endingsymbols. The starting symbol and the ending symbol of a (e.g.,scheduled) transmission may be within the same transmission timingstructure, e.g. the same slot. However, in some cases, the ending symbolmay be in a later transmission timing structure than the startingsymbol, in particular a structure following in time. To a scheduledtransmission, a duration may be associated and/or indicated, e.g. in anumber of symbols or associated time intervals. In some variants, theremay be different transmissions scheduled in the same transmission timingstructure. A scheduled transmission may be considered to be associatedto a specific channel, e.g. a shared channel like PUSCH or PDSCH.

A transmission timing structure may comprise a plurality of symbols,and/or define an interval comprising several symbols (respectively theirassociated time intervals). In the context of this disclosure, it shouldbe noted that a reference to a symbol for ease of reference may beinterpreted to refer to the time domain projection or time interval ortime component or duration or length in time of the symbol, unless it isclear from the context that the frequency domain component also has tobe considered. Examples of transmission timing structures include slot,subframe, mini-slot (which also may be considered a substructure of aslot), slot aggregation (which may comprise a plurality of slots and maybe considered a superstructure of a slot), respectively their timedomain component. A transmission timing structure may generally comprisea plurality of symbols defining the time domain extension (e.g.,interval or length or duration) of the transmission timing structure,and arranged neighboring to each other in a numbered sequence. A timingstructure (which may also be considered or implemented assynchronisation structure) may be defined by a succession of suchtransmission timing structures, which may for example define a timinggrid with symbols representing the smallest grid structures. Atransmission timing structure, and/or a border symbol or a scheduledtransmission may be determined or scheduled in relation to such a timinggrid. A transmission timing structure of reception may be thetransmission timing structure in which the scheduling control signalingis received, e.g. in relation to the timing grid. A transmission timingstructure may in particular be a slot or subframe or in some cases, amini-slot.

Signaling may generally comprise one or more symbols and/or signalsand/or messages. A signal may comprise and/or represent one or morebits, which may be modulated into a common modulated signal. Anindication may represent signaling, and/or be implemented as a signal,or as a plurality of signals. One or more signals may be included inand/or represented by a message. Signaling, in particular controlsignaling, may comprise a plurality of signals and/or messages, whichmay be transmitted on different carriers and/or be associated todifferent acknowledgement signaling processes, e.g. representing and/orpertaining to one or more such processes. An indication may comprisesignaling and/or a plurality of signals and/or messages and/or may becomprised therein, which may be transmitted on different carriers and/orbe associated to different acknowledgement signaling processes, e.g.representing and/or pertaining to one or more such processes.

Signaling utilising, and/or on and/or associated to, resources or aresource structure may be signaling covering the resources or structure,signaling on the associated frequency/ies and/or in the associated timeinterval/s. It may be considered that a signaling resource structurecomprises and/or encompasses one or more substructures, which may beassociated to one or more different channels and/or types of signalingand/or comprise one or more holes (resource element/s not scheduled fortransmissions or reception of transmissions). A resource substructure,e.g. a feedback resource structure, may generally be continuous in timeand/or frequency, within the associated intervals. It may be consideredthat a substructure, in particular a feedback resource structure,represents a rectangle filled with one or more resource elements intime/frequency space. However, in some cases, a resource structure orsubstructure, in particular a frequency resource range, may represent anon-continuous pattern of resources in one or more domains, e.g. timeand/or frequency. The resource elements of a substructure may bescheduled for associated signaling.

It should generally be noted that the number of bits or a bit rateassociated to specific signaling that can be carried on a resourceelement may be based on a modulation and coding scheme (MCS). Thus, bitsor a bit rate may be seen as a form of resources representing a resourcestructure or range in frequency and/or time, e.g. depending on MCS. TheMCS may be configured or configurable, e.g. by control signaling, e.g.DCI or MAC (Medium Access Control) or RRC (Radio Resource Control)signaling.

A resource structure in frequency domain (which may be referred to asfrequency interval and/or range) may be represented by a subcarriergrouping. A subcarrier grouping may comprise one or more subcarriers,each of which may represent a specific frequency interval, and/orbandwidth. The bandwidth of a subcarrier, the length of the interval infrequency domain, may be determined by the subcarrier spacing and/ornumerology. The subcarriers may be arranged such that each subcarrierneighbours at least one other subcarrier of the grouping in frequencyspace (for grouping sizes larger than 1). The subcarriers of a groupingmay be associated to the same carrier, e.g. configurably or configuredof predefined. A physical resource block may be consideredrepresentative of a grouping (in frequency domain). A subcarriergrouping may be considered to be associated to a specific channel and/ortype of signaling, it transmission for such channel or signaling isscheduled and/or transmitted and/or intended and/or configured for atleast one, or a plurality, or all subcarriers in the grouping. Suchassociation may be time-dependent, e.g. configured or configurable orpredefined, and/or dynamic or semi-static. The association may bedifferent for different devices, e.g. configured or configurable orpredefined, and/or dynamic or semi-static. Patterns of subcarriergroupings may be considered, which may comprise one or more subcarriergroupings (which may be associated to same or differentsignalings/channels), and/or one or more groupings without associatedsignaling (e.g., as seen from a specific device). An example of apattern is a comb, for which between pairs of groupings associated tothe same signaling/channel there are arranged one or more groupingsassociated to one or more different channels and/or signaling types,and/or one or more groupings without associated channel/signaling).

Example types of signaling comprise signaling of a specificcommunication direction, in particular, uplink signaling, downlinksignaling, sidelink signaling, as well as reference signaling (e.g., SRSor CRS or CSI-RS), communication signaling, control signaling, and/orsignaling associated to a specific channel like PUSCH, PDSCH, PUCCH,PDCCH, PSCCH, PSSCH, etc.).

In this disclosure, for purposes of explanation and not limitation,specific details are set forth (such as particular network functions,processes and signaling steps) in order to provide a thoroughunderstanding of the technique presented herein. It will be apparent toone skilled in the art that the present concepts and aspects may bepracticed in other variants and variants that depart from these specificdetails.

For example, the concepts and variants are partially described in thecontext of Long Term Evolution (LTE) or LTE-Advanced (LTE-A) or NewRadio mobile or wireless communications technologies; however, this doesnot rule out the use of the present concepts and aspects in connectionwith additional or alternative mobile communication technologies such asthe Global System for Mobile Communications (GSM). While describedvariants may pertain to certain Technical Specifications (TSs) of theThird Generation Partnership Project (3GPP), it will be appreciated thatthe present approaches, concepts and aspects could also be realized inconnection with different Performance Management (PM) specifications.

Moreover, those skilled in the art will appreciate that the services,functions and steps explained herein may be implemented using softwarefunctioning in conjunction with a programmed microprocessor, or using anApplication Specific Integrated Circuit (ASIC), a Digital SignalProcessor (DSP), a Field Programmable Gate Array (FPGA) or generalpurpose computer. It will also be appreciated that while the variantsdescribed herein are elucidated in the context of methods and devices,the concepts and aspects presented herein may also be embodied in aprogram product as well as in a system comprising control circuitry,e.g. a computer processor and a memory coupled to the processor, whereinthe memory is encoded with one or more programs or program products thatexecute the services, functions and steps disclosed herein.

It is believed that the advantages of the aspects and variants presentedherein will be fully understood from the foregoing description, and itwill be apparent that various changes may be made in the form,constructions and arrangement of the exemplary aspects thereof withoutdeparting from the scope of the concepts and aspects described herein orwithout sacrificing all of its advantageous effects. The aspectspresented herein can be varied in many ways.

Some useful abbreviations comprise

Abbreviation Explanation ACK/NACK Acknowledgment/NegativeAcknowledgement ARQ Automatic Repeat request BER Bit Error Rate BLERBlock Error Rate CAZAC Constant Amplitude Zero Cross Correlation CBGCode Block Group CDM Code Division Multiplex CM Cubic Metric CQI ChannelQuality Information CRC Cyclic Redundancy Check CRS Common referencesignal CSI Channel State Information CSI-RS Channel state informationreference signal DAI Downlink Assignment Indicator DCI Downlink ControlInformation DFT Discrete Fourier Transform DM(−)RS Demodulationreference signal(ing) FDM Frequency Division Multiplex HARQ HybridAutomatic Repeat Request IFFT Inverse Fast Fourier Transform MBB MobileBroadband MCS Modulation and Coding Scheme MIMOMultiple-input-multiple-output MRC Maximum-ratio combining MRTMaximum-ratio transmission MU-MIMO Multiusermultiple-input-multiple-output OFDM/A Orthogonal Frequency DivisionMultiplex/Multiple Access PAPR Peak to Average Power Ratio PDCCHPhysical Downlink Control Channel PDSCH Physical Downlink Shared ChannelPRACH Physical Random Access CHannel PRB Physical Resource Block PUCCHPhysical Uplink Control Channel PUSCH Physical Uplink Shared Channel(P)SCCH (Physical) Sidelink Control Channel (P)SSCH (Physical) SidelinkShared Channel RB Resource Block RRC Radio Resource Control SC-FDM/ASingle Carrier Frequency Division Multiplex/Multiple Access SCI SidelinkControl Information SINR Signal-to-interference-plus-noise ratio SIRSignal-to-interference ratio SNR Signal-to-noise-ratio SR SchedulingRequest SRS Sounding Reference Signal(ing) SVD Singular-valuedecomposition TDM Time Division Multiplex UCI Uplink Control InformationUE User Equipment URLLC Ultra Low Latency High Reliability CommunicationVL-MIMO Very-large multiple-input-multiple-output ZF Zero Forcing

Abbreviations may be considered to follow 3GPP usage if applicable.

1-15. (canceled)
 16. A method of operating an Integrated Access and Backhaul (IAB) node in a radio access network, the IAB node being connected to a first parent IAB node via a first backhaul link having a first timing, and being connected to a second parent IAB node via a second backhaul link having a second timing, the method comprising: providing a communication link for access or backhaul, the communication link having a communication timing based on the first timing and the second timing.
 17. The method of claim 16, wherein the method comprises basing the timing of transmission by the IAB node on the communication link on the communication timing.
 18. The method of claim 16, wherein method comprises basing the timing of reception by the IAB node on the communication link on the communication timing.
 19. The method of claim 16, wherein the method comprises basing the communication timing on a function of the first timing and the second timing.
 20. The method of claim 16, wherein the first timing is based on control signaling indicating timing and/or synchronization received from the first parent node, for the first backhaul link, and/or the second timing is based on control signaling indicating timing and/or synchronization received from the second parent node, for the second backhaul link.
 21. The method of claim 16, wherein the method comprises basing the communication timing on a timing synchronized relative to a donor node.
 22. The method of claim 16, wherein the method comprises basing the communication timing on a weighted sum of the first timing and the second timing.
 23. The method of claim 16, wherein the method comprises basing the communication timing on received power and/or signal quality.
 24. The method of claim 16, wherein the IAB node is connected, or adapted to be connected or connectable, to a plurality of parent nodes via associated backhaul links with corresponding timings.
 25. The method of claim 16, wherein the method comprises basing the communication timing on the number of parent nodes of the IAB node, and/or hop-count of a parent.
 26. The method of claim 16, wherein the method comprises basing the communication timing on link latency and/or propagation delay.
 27. The method of claim 16, wherein the method comprises basing the communication timing on historical information and/or numerology.
 28. A network node for a radio access network, the network node being an Integrated Access and Backhaul (IAB) node, the network node comprising: radio circuitry; processing circuitry operatively coupled to the radio circuitry, wherein the processing circuitry is configured to: connect the network node to a first parent IAB node via a first backhaul link having a first timing; connect the network node to a second parent IAB node via a second backhaul link having a second timing; and provide a communication link for access or backhaul, the communication link having a communication timing based on the first timing and the second timing.
 29. A non-transitory computer-readable medium comprising, stored thereupon, computer program instructions configured for execution by a network node being an Integrated Access and Backhaul (IAB) node, the computer program instructions being configured to cause the network node to: connect the network node to a first parent IAB node via a first backhaul link having a first timing; connect the network node to a second parent IAB node via a second backhaul link having a second timing; and provide a communication link for access or backhaul, the communication link having a communication timing based on the first timing and the second timing. 